The present invention relates a golf club head, and particularly relates to an improvement of a golf club head.
Generally, a head of an iron club is integrally made of a metal material such as soft iron, brass, stainless steel, or the like.
A golf club head of this kind has a shape and weight which are made to correspond to each club number. Being a mass of metal, however, an iron club head is poor in elasticity. Particularly, in the case where a ball hitting surface of the club head which is most important in hitting a ball has less elasticity, the coefficient of restitution of the ball hitting surface is so small that it is impossible to obtain a soft ball-hitting feeling as well as a long ball-flying distance unlike a wood club.
Conventionally, as disclosed in Japanese Utility Model Unexamined Publication No. sho-61-139256, or as shown in FIG. 8 of this application, a hosel portion 1 for connection with a shaft, a sole portion 3, and a thin frame portion 7 defining the contour of a base metal body portion 5 are integrally made of a metal material such as soft iron, stainless steel, or the like. Further, as shown in FIG. 9, a filling member 11 made of fiber-reinforced resin mainly including carbon fibers is filled in a hollow portion 9 formed inside the thin frame portion 7, and the thin frame portion 7 and the filling member 11 are covered with fiber-reinforced resin 13 mainly including carbon fibers so that it is possible to improve repulsion force of the ball hitting surface and it is possible to obtain soft ball-hitting feeling in hitting a ball. In the drawing, the reference numeral 15 designates a shaft and 17 designates a face plate.
Further, an iron club head in which not only inertia moment and repulsion force are increased but buffer against impact distortion transmitted to a player at the time of impact is provided, is disclosed in Japanese Utility Model Unexamined Publication No. Sho-60-49868.
This golf club head has a configuration in which, as shown in FIGS. 10 and 11, recess portions 25 and 27 are formed respectively in the substantially central portions or face surfaces 21 and 23 opposite to each other of a base metal body 19 made of a metal material such as soft iron, stainless steel or the like, a number of fine holes 29 are formed in the bottom portions of the respective recess portions 25 and 27 so as to make the recess portions 25 and 27 have grid structures respectively, and a face body 31 and a back face body 33 made of fiber-reinforced resin or the like are mounted in the recess portions 25 and 27 respectively.
In such a conventional golf club head of this kind, however, it is general that a sole portion 3 is made heavy so that a top portion opposing to the sole portion 3 through the hollow portion 9, as shown in FIG. 8, is lighter in weight than the sole portion 3.
In such a conventional golf club head, therefore, the return of the sole portion 3 is faster than the top portion at the time of swinging so that a hit ball is apt to fly high. Accordingly, it has been difficult to hit a liner ball without being influenced by wind.
Further, also in the golf club head shown in FIG. 10, there is no positive description about the weight balance between the sole and top portions of the base metal body on the opposite sides of the concave portions 25 and 27 in the specification of the Japanese Utility Model Unexamined Publication No. Sho-60-49868. In the case where the sole portion 3 is heavier than the top portion as shown in the drawing, the return of the sole portion is faster than that of the top portion at the time of swinging so that it has been difficult to hit a liner ball.